This invention relates to a battery charge indicating circuit, such as that used in a motor vehicle, and more particularly to a circuit for indicating the overcharging of a battery.
In a conventional circuit of this type when the ignition system of a vehicle is turned on, but the engine is not running, an indicating lamp is illuminated to indicate the non-charging of the battery. Upon starting the engine the indicating lamp is turned off as the output voltage of the alternator rises.
If the output voltage of the alternator drops to zero for some reason during the operation of the engine, the indicating lamp is illuminated to warn the driver of the battery discharge. However, if the output voltage of the alternator becomes extremely high due to faults, for example, in the voltage regulator while the engine is running normally, the indicating lamp remains off. Also, if the connection between the alternator output rectifier and the battery is broken while the voltage regulator is operating normally, the indicating lamp is only dimly illuminated or flickered, and does not provide an adequate warning to the driver of the battery discharge.